boost/utility/result_of.hpp
// Boost result_of library
// Copyright Douglas Gregor 2004. Use, modification and
// distribution is subject to the Boost Software License, Version
// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// For more information, see http://www.boost.org/libs/utility
#ifndef BOOST_RESULT_OF_HPP
#define BOOST_RESULT_OF_HPP
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/type_traits/is_class.hpp>
#include <boost/type_traits/is_pointer.hpp>
#include <boost/type_traits/is_member_function_pointer.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/declval.hpp>
#include <boost/type_traits/conditional.hpp>
#include <boost/type_traits/type_identity.hpp>
#include <boost/type_traits/integral_constant.hpp>
#include <boost/core/enable_if.hpp>
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
# undef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES
# define BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES
#endif
#ifdef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES
# include <boost/preprocessor/cat.hpp>
# include <boost/preprocessor/iteration/iterate.hpp>
# include <boost/preprocessor/repetition/enum_params.hpp>
# include <boost/preprocessor/repetition/enum_trailing_params.hpp>
# include <boost/preprocessor/repetition/enum_binary_params.hpp>
# include <boost/preprocessor/repetition/enum_shifted_params.hpp>
# include <boost/preprocessor/facilities/intercept.hpp>
#endif
#ifndef BOOST_UTILITY_DOCS
#ifndef BOOST_RESULT_OF_NUM_ARGS
# define BOOST_RESULT_OF_NUM_ARGS 16
#endif
#endif // BOOST_UTILITY_DOCS
// Use the decltype-based version of result_of by default if the compiler
// supports N3276 <http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2011/n3276.pdf>.
// The user can force the choice by defining BOOST_RESULT_OF_USE_DECLTYPE,
// BOOST_RESULT_OF_USE_TR1, or BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK but not more than one!
#if (defined(BOOST_RESULT_OF_USE_DECLTYPE) && defined(BOOST_RESULT_OF_USE_TR1)) || \
(defined(BOOST_RESULT_OF_USE_DECLTYPE) && defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)) || \
(defined(BOOST_RESULT_OF_USE_TR1) && defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK))
# error More than one of BOOST_RESULT_OF_USE_DECLTYPE, BOOST_RESULT_OF_USE_TR1 and \
BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK cannot be defined at the same time.
#endif
#ifndef BOOST_UTILITY_DOCS
#ifndef BOOST_RESULT_OF_USE_TR1
# ifndef BOOST_RESULT_OF_USE_DECLTYPE
# ifndef BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK
# ifndef BOOST_NO_CXX11_DECLTYPE_N3276 // this implies !defined(BOOST_NO_CXX11_DECLTYPE)
# define BOOST_RESULT_OF_USE_DECLTYPE
# else
# define BOOST_RESULT_OF_USE_TR1
# endif
# endif
# endif
#endif
#endif // BOOST_UTILITY_DOCS
namespace boost {
template<typename F> struct result_of;
template<typename F> struct tr1_result_of; // a TR1-style implementation of result_of
#if !defined(BOOST_NO_SFINAE)
namespace detail {
typedef char result_of_yes_type; // sizeof(result_of_yes_type) == 1
typedef char (&result_of_no_type)[2]; // sizeof(result_of_no_type) == 2
template<class T> struct result_of_has_type {};
template<class T> struct result_of_has_result_type_impl
{
template<class U> static result_of_yes_type f( result_of_has_type<typename U::result_type>* );
template<class U> static result_of_no_type f( ... );
typedef boost::integral_constant<bool, sizeof(f<T>(0)) == sizeof(result_of_yes_type)> type;
};
template<class T> struct result_of_has_result_type: result_of_has_result_type_impl<T>::type
{
};
// Work around a nvcc bug by only defining has_result when it's needed.
#ifdef BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK
template<template<class> class C> struct result_of_has_template {};
template<class T> struct result_of_has_result_impl
{
template<class U> static result_of_yes_type f( result_of_has_template<U::template result>* );
template<class U> static result_of_no_type f( ... );
typedef boost::integral_constant<bool, sizeof(f<T>(0)) == sizeof(result_of_yes_type)> type;
};
template<class T> struct result_of_has_result: result_of_has_result_impl<T>::type
{
};
#endif
template<typename F, typename FArgs, bool HasResultType> struct tr1_result_of_impl;
template<typename F> struct cpp0x_result_of;
#ifdef BOOST_NO_SFINAE_EXPR
// There doesn't seem to be any other way to turn this off such that the presence of
// the user-defined operator,() below doesn't cause spurious warning all over the place,
// so unconditionally turn it off.
#if BOOST_MSVC
# pragma warning(disable: 4913) // user defined binary operator ',' exists but no overload could convert all operands, default built-in binary operator ',' used
#endif
struct result_of_private_type {};
struct result_of_weird_type {
friend result_of_private_type operator,(result_of_private_type, result_of_weird_type);
};
template<typename T>
result_of_no_type result_of_is_private_type(T const &);
result_of_yes_type result_of_is_private_type(result_of_private_type);
template<typename C>
struct result_of_callable_class : C {
result_of_callable_class();
typedef result_of_private_type const &(*pfn_t)(...);
operator pfn_t() const volatile;
};
template<typename C>
struct result_of_wrap_callable_class {
typedef result_of_callable_class<C> type;
};
template<typename C>
struct result_of_wrap_callable_class<C const> {
typedef result_of_callable_class<C> const type;
};
template<typename C>
struct result_of_wrap_callable_class<C volatile> {
typedef result_of_callable_class<C> volatile type;
};
template<typename C>
struct result_of_wrap_callable_class<C const volatile> {
typedef result_of_callable_class<C> const volatile type;
};
template<typename C>
struct result_of_wrap_callable_class<C &> {
typedef typename result_of_wrap_callable_class<C>::type &type;
};
template<typename F, bool TestCallability = true> struct cpp0x_result_of_impl;
#else // BOOST_NO_SFINAE_EXPR
template<typename T>
struct result_of_always_void
{
typedef void type;
};
template<typename F, typename Enable = void> struct cpp0x_result_of_impl {};
#endif // BOOST_NO_SFINAE_EXPR
template<typename F>
struct result_of_void_impl
{
typedef void type;
};
template<typename R>
struct result_of_void_impl<R (*)(void)>
{
typedef R type;
};
template<typename R>
struct result_of_void_impl<R (&)(void)>
{
typedef R type;
};
// Determine the return type of a function pointer or pointer to member.
template<typename F, typename FArgs>
struct result_of_pointer
: tr1_result_of_impl<typename remove_cv<F>::type, FArgs, false> { };
template<typename F, typename FArgs>
struct tr1_result_of_impl<F, FArgs, true>
{
typedef typename F::result_type type;
};
template<typename FArgs>
struct is_function_with_no_args : false_type {};
template<typename F>
struct is_function_with_no_args<F(void)> : true_type {};
template<typename F, typename FArgs>
struct result_of_nested_result : F::template result<FArgs>
{};
template<typename F, typename FArgs>
struct tr1_result_of_impl<F, FArgs, false>
: conditional<is_function_with_no_args<FArgs>::value,
result_of_void_impl<F>,
result_of_nested_result<F, FArgs> >::type
{};
} // end namespace detail
#ifndef BOOST_RESULT_OF_NO_VARIADIC_TEMPLATES
# include <boost/utility/detail/result_of_variadic.hpp>
#else
# define BOOST_PP_ITERATION_PARAMS_1 (3,(0,BOOST_RESULT_OF_NUM_ARGS,<boost/utility/detail/result_of_iterate.hpp>))
# include BOOST_PP_ITERATE()
#endif
#if 0
// inform dependency trackers, as they can't see through macro includes
#include <boost/utility/detail/result_of_iterate.hpp>
#endif
#else
# define BOOST_NO_RESULT_OF 1
#endif
}
#endif // BOOST_RESULT_OF_HPP